80+ Interview Questions and Answers

Javascript code to find frequency of characters in a sentence and difference between dynamic and static initialization.

• To find frequency of characters in a sentence, create an object and iterate over each character in the sentence. Increment the count of each character in the object.

• Dynamic initialization refers to initializing a variable at runtime, while static initialization refers to initializing a variable at compile time.

• Example of dynamic initialization: int x = new in...read more

To optimize a complex API, consider reducing unnecessary data transfer, caching frequently accessed data, using efficient data structures, and implementing proper error handling.

• Identify and remove unnecessary data transfer to reduce latency

• Implement caching mechanisms for frequently accessed data to improve performance

• Use efficient data structures and algorithms to optimize processing speed

• Implement proper error handling to ensure robustness and reliability

• Consider implement...read more

Questions on Java basics - .equals() vs ==, Fibonacci series, and MultiThreading.

• The .equals() function compares the values of two objects, while == compares their memory addresses.

• Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones.

• MultiThreading is a technique where multiple threads of execution run concurrently within a single program.

• Examples: 5 == 5 is true, but new String('hello') == new String('hello') is false.

• Fibonacci ser...read more

To print second highest number in a list of integers in Java

• Sort the list in descending order

• Print the second element in the sorted list

Find the second largest number from an array of strings.

• Convert the array of strings to an array of numbers.

• Sort the array in descending order.

• Return the second element of the sorted array.

The difference between == and === is that == checks for equality after type conversion, while === checks for equality without type conversion.

• == is a loose equality comparison operator that performs type coercion before comparing two values.

• === is a strict equality comparison operator that does not perform type coercion before comparing two values.

• Example: 5 == '5' will return true because the values are equal after type coercion, but 5 === '5' will return false because they ...read more

App life cycle involves various stages like launch, background, inactive, active, and termination. App delegate methods manage these stages.

• App delegate methods are used to respond to important events in the app's life cycle, such as app launch, backgrounding, foregrounding, and termination.

• Some of the key methods in the app delegate include application(_:didFinishLaunchingWithOptions:), applicationDidEnterBackground(_ :), applicationDidBecomeActive(_ :), and applicationWillT...read more

OOPs (Object-Oriented Programming) is a programming paradigm that uses objects to represent and manipulate data.

• OOPs is based on the concept of classes and objects.

• It allows for encapsulation, inheritance, and polymorphism.

• Objects have properties (attributes) and behaviors (methods).

• Example: In a banking system, a class 'Account' can have objects representing individual bank accounts.

Exceptions are events that occur during the execution of a program that disrupts the normal flow of instructions.

• Exceptions are objects that are thrown at runtime when an abnormal condition occurs

• They can be caught and handled using try-catch blocks

• Java has a hierarchy of exception classes, with the base class being Throwable

• Checked exceptions must be handled or declared in the method signature

• Unchecked exceptions do not need to be handled or declared

Concatenate strings in array until total length is greater than 1

• Iterate through array and concatenate strings until length is greater than 1

• Use a loop to keep adding strings until total length exceeds 1

• Check total length after each concatenation to ensure it is greater than 1

Selenium can be used for testing responsiveness of mobile apps.

• Selenium can simulate user interactions on mobile apps to test responsiveness.

• It can be used to test how the app responds to different screen sizes and orientations.

• Selenium can also be used to test how the app responds to different network conditions.

• Examples of responsiveness testing using Selenium include checking if buttons and links are clickable, if images and videos load properly, and if the app adjusts to ...read more

Oops concepts are fundamental principles in object-oriented programming that help in organizing and designing code efficiently.

• Encapsulation: Wrapping data and methods into a single unit (class). Example: Class Car with properties like make, model, and methods like start(), stop().

• Inheritance: Reusing code from existing classes to create new classes. Example: Class SUV inheriting from class Car.

• Polymorphism: Ability of objects to take on multiple forms. Example: Overloading a...read more

MySQL query to find 2 highest salaries and explanation of abstract and interfaces

• Use ORDER BY and LIMIT to get the top 2 salaries

• Abstract classes cannot be instantiated and can have both abstract and non-abstract methods

• Interfaces define a set of methods that a class must implement

• Example: SELECT salary FROM employees ORDER BY salary DESC LIMIT 2

• Example: abstract class Animal { abstract void makeSound(); }

• Example: interface Vehicle { void start(); void stop(); }

Find the defective iron rod among 8 rods of 1kg with minimum number of weighs.

• Divide the rods into 3 groups of 3, 3, and 2 rods each.

• Weigh the first two groups against each other.

• If they balance, the defective rod is in the third group.

• If they don't balance, the defective rod is in the heavier group.

• Divide the heavier group into two groups of 1 and 1 or 2 and 2 rods each.

• Weigh the two rods against each other.

• If they balance, the defective rod is the remaining one.

• If they don'...read more

To connect to a database, you need to use a database connection string with the appropriate credentials.

• Use a database connection string with the necessary information such as server address, database name, username, and password.

• Choose the appropriate database driver for the type of database you are connecting to (e.g. MySQL, PostgreSQL, MongoDB).

• Establish a connection using a programming language-specific database library or framework (e.g. JDBC for Java, psycopg2 for Pytho...read more

Reverse a string while preserving white spaces

• Iterate through the string from end to start

• Keep track of white spaces and insert them in the reversed string

• Example: 'hello world' -> 'dlrow olleh'

Comparator and Comparable are interfaces used for sorting objects in Java.

• Comparable interface is used to define the natural ordering of objects.

• Comparator interface is used to define custom ordering of objects.

• Comparable interface has compareTo() method while Comparator interface has compare() method.

• Comparable interface is implemented by the class whose objects need to be sorted while Comparator interface is implemented by a separate class.

• Example: String class implements C...read more

URL Session using completions is a way to handle network requests in iOS development.

• URL Session is a class in iOS used for making network requests.

• Completions are closures that are called when a network request completes.

• Using completions allows for handling the response data or errors after a network request.

• Example: URLSession.shared.dataTask(with: url) { (data, response, error) in }

Reversing a linked list involves changing the direction of the pointers in the list.

• Iterate through the list and change the direction of the pointers

• Use three pointers to keep track of the current node, previous node, and next node

• Update the head of the list to be the last node after reversing

LLD Design for Movie Ticket Booking System(BookMyShow.com)

• Use case diagram to identify actors and their interactions

• Class diagram to represent entities like User, Movie, Theater, Booking

• Sequence diagram to show the flow of events during ticket booking process

View life cycle refers to the process of creating, updating, and destroying views in an Android application.

• View life cycle includes methods like onCreate, onStart, onResume, onPause, onStop, and onDestroy.

• These methods are called at different stages of a view's life cycle, allowing developers to perform actions like initializing UI components, saving instance state, and releasing resources.

• For example, onCreate is called when a view is first created, onStart is called when t...read more

Object-oriented programming concepts focus on classes, objects, inheritance, encapsulation, and polymorphism.

• Classes: Blueprint for creating objects with attributes and methods.

• Objects: Instances of classes that contain data and behavior.

• Inheritance: Ability for a class to inherit attributes and methods from another class.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Polymorphism: Ability for objects of different classes to respond to th...read more

Agile metrics include velocity, burn-down chart, lead time, cycle time. Waterfall metrics include schedule variance, cost variance, and earned value.

• Agile metrics focus on team performance and progress towards goals

• Velocity measures the amount of work completed in a sprint

• Burn-down chart shows the remaining work in a sprint

• Lead time measures the time from start to finish of a task

• Cycle time measures the time from when work begins on a task to when it is completed

• Waterfall met...read more

OOPs is Object-Oriented Programming, polymorphism allows objects to be treated as instances of their parent class, abstract class cannot be instantiated.

• OOPs is a programming paradigm based on the concept of objects, which can contain data in the form of fields and code in the form of procedures.

• Polymorphism allows objects to be treated as instances of their parent class, enabling different classes to be treated as instances of a common superclass.

• Abstract class is a class th...read more

ACID properties are a set of properties that guarantee reliable database transactions.

• Atomicity: All operations in a transaction are completed successfully or none at all.

• Consistency: Database remains in a consistent state before and after the transaction.

• Isolation: Transactions are isolated from each other until they are completed.

• Durability: Once a transaction is committed, changes are permanent and cannot be lost.

• Example: Transfer of funds between two bank accounts must be...read more

I am open to opportunities in various locations, with a preference for cities with a strong tech industry.

• Open to various locations

• Preference for cities with strong tech industry

Code to remove duplicate letters from a string and print remaining letters or 0 if no duplicates.

• Iterate through the string and keep track of seen characters using a set

• If a character is not in the set, add it to the set and append it to the result string

• If a character is already in the set, do not append it to the result string

• If the result string is empty, print 0

Sorting an array of strings in alphabetical order.

• Use a sorting algorithm like quicksort or mergesort.

• Compare strings using built-in functions like strcmp in C++ or compareTo in Java.

• Consider using a custom comparator function for sorting in languages like JavaScript.

The value of 2 raised to the power of 12 is 4096.

• 2 raised to the power of 12 is calculated by multiplying 2 by itself 12 times.

• The result is obtained by multiplying 2 by itself: 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 = 4096.

Prototype in JS refers to the mechanism by which objects in JavaScript inherit properties and methods from other objects.

• Prototype chain allows objects to inherit properties and methods from other objects

• Prototype-based inheritance is a key feature of JavaScript

• Example: Creating a new object using a constructor function and adding methods to its prototype

To reduce bundle size of an Angular application, you can use lazy loading, tree shaking, code splitting, and optimizing assets.

• Use lazy loading to load modules only when needed

• Implement tree shaking to remove unused code

• Utilize code splitting to divide code into smaller chunks

• Optimize assets by compressing images and minifying CSS/JS files

Fill the 5L jar, pour 2L to the 2L jar, empty the 2L jar, pour the remaining 3L from 5L jar to 2L jar, fill 5L jar again, pour 1L to 2L jar, then pour the remaining 4L to the 2L jar.

• Fill 5L jar

• Pour 2L to 2L jar

• Empty 2L jar

• Pour remaining 3L from 5L jar to 2L jar

• Fill 5L jar again

• Pour 1L to 2L jar

• Pour remaining 4L to 2L jar

Risk is a potential future problem, while an issue is a current problem that needs to be addressed.

• Risk is a potential future event that may or may not happen, while an issue is a current problem that needs to be resolved.

• Risk can be identified and managed proactively, while issues need to be addressed reactively.

• Risk can have a positive or negative impact on the project, while issues always have a negative impact.

• Examples of risks include changes in scope, resource availabil...read more

Retesting is testing the same functionality again after fixing the defects. Regression testing is testing the unchanged functionality after making changes in the software.

• Retesting is done to ensure that the defects reported earlier have been fixed.

• Regression testing is done to ensure that the changes made in the software have not affected the existing functionality.

• Retesting is a subset of regression testing.

• Retesting is done after fixing the defects, while regression testin...read more

I can perform in a new domain by researching, learning, and adapting quickly.

• Conduct thorough research on the new domain

• Learn the key concepts and terminology

• Identify similarities and differences with previous domains

• Adapt quickly to new processes and procedures

• Collaborate with team members and seek guidance when needed

Optimisation techniques for software engineering

• Use efficient algorithms and data structures

• Minimize I/O operations and network calls

• Optimize database queries

• Use caching and memoization

• Parallelize computations

• Profile and analyze code for bottlenecks

• Eliminate unnecessary code and dependencies

The red and yellow cards in football indicate disciplinary actions taken by the referee.

• A red card is shown to a player who has committed a serious offense and results in the player being sent off the field.

• A yellow card is shown as a caution to a player for a less serious offense.

• If a player receives two yellow cards in a single match, it is equivalent to a red card and the player is sent off.

• Red and yellow cards help maintain discipline and fair play in football.

Design patterns are reusable solutions to common software problems.

• Design patterns provide a common language for developers to communicate solutions.

• They help improve code quality, maintainability, and scalability.

• Examples include Singleton, Factory, Observer, and Decorator patterns.

Tags can be used to categorize test cases and run specific groups of tests.

• Add tags to test cases in the test management tool or test automation framework

• Use the tags to filter and select specific test cases to run

• Run tests based on tags using command line options or configuration settings

Retesting is testing the same functionality again to ensure the defect is fixed, while regression testing is testing the whole application to ensure new changes do not affect existing functionality.

• Retesting focuses on verifying that a specific defect has been fixed.

• Regression testing focuses on ensuring that new changes do not impact existing functionality.

• Retesting is usually performed by the tester who found the defect.

• Regression testing is typically performed by the testi...read more

System testing focuses on testing the entire system as a whole, while system integration testing focuses on testing the interactions between integrated components.

• System testing ensures that the entire system meets the specified requirements and functions correctly.

• System integration testing focuses on testing the interfaces and interactions between integrated components to ensure they work together seamlessly.

• System testing is performed after integration testing to validate ...read more

To lead a DevOps team, I would focus on communication, collaboration, and continuous improvement.

• Establish clear goals and expectations for the team

• Encourage open communication and collaboration between team members

• Implement agile methodologies and continuous improvement processes

• Provide opportunities for professional development and training

• Ensure that the team has the necessary tools and resources to succeed

• Lead by example and foster a culture of innovation and experimentat...read more

Xpath for locating elements in Amazon website.

• Use // to start the Xpath expression

• Use @attribute='value' to specify the attribute and its value

• Use text()='text' to specify the text of the element

• Use [index] to specify the index of the element if there are multiple matching elements

Java program to check if a number is a palindrome or not.

• Convert the number to a string to easily check for palindrome

• Reverse the string and compare it with the original string to check for palindrome

• Handle edge cases like negative numbers and single-digit numbers

Pure pipes do not have any side effects and always return the same output for the same input, while impure pipes can have side effects and may not return the same output for the same input.

• Pure pipes are stateless and deterministic.

• Impure pipes can have side effects like modifying global variables or making network requests.

• Examples of pure pipes include filters in Angular, while examples of impure pipes include async pipes in Angular.

Testing ensures software quality and reduces the risk of defects in production.

• Testing helps identify defects and bugs early in the development cycle.

• It ensures that the software meets the requirements and specifications.

• Testing helps improve the overall quality of the software.

• It reduces the risk of defects and failures in production.

• Testing helps build trust and confidence in the software among stakeholders.

Scenarios are high-level descriptions of user actions and system responses, while test cases are specific steps to verify functionality.

• Scenarios describe user interactions with the system, while test cases verify specific functionality.

• Scenarios are often used in the early stages of testing to identify potential issues, while test cases are used for more detailed testing.

• Scenarios can be used to create test cases, but not all scenarios will have corresponding test cases.

• Test...read more

Runner/Config file is used in test frameworks to manage test execution and configuration settings.

• Runner file is used to execute test cases in a specific order or grouping.

• Config file is used to store configuration settings like browser type, environment variables, etc.

• Separating runner and config files helps in better organization and maintenance of test suites.

8 to the power of 4 is equal to 4096.

• To calculate 8 to the power of 4, you multiply 8 by itself 4 times.

• 8^4 = 8 * 8 * 8 * 8 = 4096.

DEFECT LIFE CYCLE is the process of identifying, reporting, prioritizing, and resolving software defects.

• Defect is identified by testers during testing

• Defect is reported to development team

• Development team prioritizes and resolves the defect

• Defect is retested by testers

• If defect is fixed, it is closed, else it goes back to development team

• Defect life cycle ends when all defects are resolved

Iterate through the table to find the second largest value.

• Iterate through the table and keep track of the largest and second largest values.

• Compare each value with the current largest and second largest values.

• Update the second largest value if a new value is found that is greater than the current second largest value.

Test cases for video game

• Test game mechanics and controls

• Test graphics and animations

• Test audio and sound effects

• Test game performance and stability

• Test multiplayer functionality

Pre requisites of API testing include understanding of API documentation, knowledge of HTTP methods, familiarity with testing tools.

• Understanding of API documentation

• Knowledge of HTTP methods (GET, POST, PUT, DELETE)

• Familiarity with testing tools like Postman or SoapUI

• Ability to write test cases for API endpoints

• Understanding of status codes and response formats

Use bitwise XOR operation to swap two numbers without using a temporary variable.

• Use XOR operation to swap two numbers without using a temporary variable.

• a = a XOR b

• b = a XOR b

• a = a XOR b

Multithreading in Java allows multiple threads to run concurrently within a single program.

• Java provides built-in support for multithreading through the java.lang.Thread class.

• Threads can be created by extending the Thread class or implementing the Runnable interface.

• Synchronization is used to prevent multiple threads from accessing shared resources simultaneously.

• Thread pools can be used to manage a group of threads for efficient resource utilization.

• Java 8 introduced the Co...read more

Remove duplicates from list of strings

• Create a Set to store unique strings

• Iterate through the array and add each string to the Set

• Convert the Set back to an array to get the list of unique strings

Sort array of strings in descending order

• Use a sorting algorithm like quicksort or mergesort

• Specify the sorting order as descending

• Ensure the sorting algorithm is stable to maintain order of equal elements

SDLC stands for Software Development Life Cycle, which is a process used to design, develop, and test software.

• SDLC is a framework that outlines the steps involved in software development.

• It includes planning, designing, coding, testing, and maintenance.

• Each phase of SDLC has its own set of deliverables and objectives.

• SDLC models include Waterfall, Agile, and DevOps.

• The choice of SDLC model depends on the project requirements and team's expertise.

STLC stands for Software Testing Life Cycle, which is a process followed to ensure quality in software testing.

• STLC is a sequential process that includes planning, designing, executing, and reporting.

• It involves various stages like requirement analysis, test planning, test design, test execution, and test closure.

• The main objective of STLC is to ensure that the software meets the customer's requirements and is of high quality.

• STLC helps in identifying defects early in the dev...read more

QuickSort is a popular sorting algorithm

• Divide and conquer approach

• Uses a pivot element to partition the array

• Recursively sorts the sub-arrays

• Time complexity: O(n log n)

• Example: [5, 2, 9, 3, 7, 6, 8] -> [2, 3, 5, 6, 7, 8, 9]

Our current framework is a hybrid framework combining data-driven and keyword-driven approaches.

• Combines data-driven and keyword-driven testing

• Uses Excel sheets for test data and keywords

• Utilizes Selenium WebDriver for automation

• Includes reusable functions for common actions

• Supports parallel execution for faster testing

XPath can be used to locate frames in HTML documents.

• Use the 'frame' or 'iframe' tag name in the XPath expression

• Use the 'id' or 'name' attribute to locate a specific frame

• Use the 'index' to locate a frame by its position in the document

Unit testing is a type of software testing where individual units or components of a software application are tested in isolation.

• Unit testing is done by developers during the development phase

• It helps to identify defects early in the development cycle

• It ensures that each unit/component of the software application is working as expected

• It helps to improve the quality of the software application

• Examples of unit testing frameworks include JUnit, NUnit, and PHPUnit

User stories for an MS Application

• As a user, I want to be able to create new documents in Word.

• As a user, I want to be able to format text in Excel.

• As a user, I want to be able to set reminders in Outlook.

• As a user, I want to be able to collaborate with others in PowerPoint.

• As a user, I want to be able to customize templates in Publisher.

QA deliverables are the tangible work products produced by the QA team during the software testing process.

• Test plans

• Test cases

• Test scripts

• Defect reports

• Test summary reports

The system design of the current project involves a microservices architecture with containerization using Docker and orchestration with Kubernetes.

• Utilizing microservices architecture for scalability and maintainability

• Containerizing applications with Docker for portability and consistency

• Orchestrating containers with Kubernetes for automated deployment and scaling

Custom hashmap design involves creating a data structure that maps keys to values for efficient retrieval.

• Use an array of linked lists to handle collisions

• Implement methods for adding, removing, and retrieving key-value pairs

• Consider resizing the hashmap when it reaches a certain load factor

As a Business Analyst, previous BAU tasks included analyzing business processes, gathering requirements, creating documentation, and facilitating communication between stakeholders.

• Analyzed current business processes to identify areas for improvement

• Gathered requirements from stakeholders to understand their needs and priorities

• Created documentation such as business requirements documents, functional specifications, and user stories

• Facilitated communication between business s...read more

A thread pool is a collection of worker threads that efficiently execute asynchronous tasks.

• Create a fixed-size queue to hold tasks.

• Create a group of worker threads that continuously take tasks from the queue and execute them.

• Implement a mechanism to add tasks to the queue for execution.

• Consider using a thread-safe data structure for the task queue.

• Ensure proper synchronization to avoid race conditions.

Find if there are three elements in an array that sum up to a given target value.

• Sort the array first to make the solution more efficient.

• Use two pointers technique to find the triplet sum.

• Handle duplicates by skipping them while iterating.

Test cases for login page functionality

• Verify valid username and password combination successfully logs in

• Verify error message is displayed for invalid username or password

• Verify 'Forgot Password' link redirects to password reset page

• Verify 'Create Account' link redirects to registration page

Cloning in Java refers to creating an exact copy of an object.

• Use the clone() method to create a shallow copy of an object.

• For deep cloning, implement the Cloneable interface and override the clone() method.

• Cloning can be used to create independent copies of objects.

Deadlock on threads occurs when two or more threads are waiting for each other to release resources, causing a standstill.

• Deadlock happens when two or more threads are blocked forever, waiting for each other to release resources.

• Prevention methods include avoiding circular wait, ensuring a fixed order of resource acquisition, and using timeouts.

• Detection methods include analyzing thread dumps, using tools like jstack or jconsole, and monitoring resource allocation.

• Example: Th...read more

Reverse a given string

• Create a new empty string to store the reversed string

• Iterate through the original string from end to start and append each character to the new string

• Return the reversed string